Refrigeration system with refrigerant operated pump



June 6, 1961 Q W D, JR 2,986,898

REFRIGERATION SYSTEM WITH REFRIGERANT OPERATED PUMP Filed Oct. 8. 1959 2Sheets-Sheet l I3 I l2 i 22 h *b /4 I 3; h ,5 I COOL/N6 l T ?NDE;VSER 2/COIL & J 42 I //7 I'll v 25, I R51. c /8 20 36 v Q 26 RE T 39 33 53 lcomp/mm? P cY '"H I 47 J I? W 47 42: 4/ J 39 REL R'EL 33 4 I R2 3 Q's l.l 52 35 T INVENTOR.

I CHARLES 1P. W001: JR

BY M, M a meeu.

OVffor-nzqs June 6, 1961 c. P. wooo, JR 2,936,893

REFRIGERATION SYSTEM WITH REFRIGERANT OPERATED PUMP Filed Oct. 8. 1959 2Sheets-Sheet 2 SUPPLYVOIATAGE Eel 3 INVENTOR. EHARLEs JP. W001: JR.

O fformzgs Uni e t Page "O 73 2,986,898 REFRIGERATION SYSTEM WITHREFRIGERANT OPERATED PUMP Charles P. Wood, IL, Cincinnati, Ohio,assignor to The Vilter Manufacturing Co., Milwaukee, Wis., a corporationof Wisconsin Filed Oct. 8, 1959, Ser. No. 845,151 Claims. (Cl. 62-174)The present invention relates generally to improvements in the art ofrefrigeration, and relates more particularly to an improvedrefrigeration system embodying a pump which is energized by therefrigerant for returning low pressure refrigerant to the high pressureside of the system.

-It has heretofore been proposed to provide a refrigerant system whichincludes a pump for forcing accumulated liquid refrigerant from anaccumulator or the like under relatively high pressure back to a storagetank or the like. However, in such instances wherein a pump wasutilized, it was common practice to energize the pump by an outside orseparate source of power, thus necessitating costly pump drivingmechanism as well as suit able controls therefor.

It has also been proposed to utilize an ejector for forcing liquid underpressure from an accumulator to a trap from which it is adapted to flowby gravity back to the high pressure receiver, and in such a system, itis customary for the ejector to be energized by the refrigerant.However, the use of an ejector does not provide positive operation andpresents serious problems with respect to control.

Accordingly, an important object of this invention is to provide animproved refrigerating system wherein novel and improved means areprovided for returning low pressure refrigerant to the high pressureside of the system and which obviates the objections and disadvantagesattendant prior systems of this general type.

Another object of the invention is to provide an improved refrigeratingsystem embodying a novel pump for returning low pressure refrigerantback to the high pressure side of the system, the pump being energizedby the refrigerant and being automatically controlled for positiveoperation in a novel manner.

Still another object of this invention is to provide an improvedrefrigerating system embodying a free piston pump energized by therefrigerant in the system and controlled by solenoid valves which are inturn actuated by means carried directly by the piston for pumping liquidfrom the accumulator to the liquid line of the receiver,

the pump being operable by high pressure gas from the condenser.

A further object of the present invention is to provide an improvedrefrigeration system which is highly efficient and positive inoperation, which is simple and economical in construction, and in whichthe operating parts are automatically controlled.

These and other objects and advantages of the invention will becomeapparent from the following detailed description.

A clear conception of the various features of the present improvementand of the mode of constructing and operating a typical refrigerationsystem embodying the invention may be had by referring to the drawingsaccompanying and forming a part of this specification in which likereference characters designate the same or similar parts in the severalviews.

FIG. 1 is a more or less diagrammatic view showing a typicalrefrigeration system embodying the invention;

FIG. 2 is a fragmentary perspective view of the refrigerant transferportion of the improved system showing the liquid pump connections;

i atented June 6, 1961 FIG. 3 is a Wiring diagram showing a suitablecontrol arrangement; and

FIG. 4 is a longitudinal section through one of the improved free pistonpumps and a part of its related actuating mechanism.

While the invention has been shown and described herein as beingembodied in a refrigeration system having a particular circuitry andarrangement of parts, it is not desired or intended to therebyunnecessarily restrict or limit the application of the invention; and itis also understood that certain descriptive terminology used hereinshall be given the broadest possible interpretation consistent with thedisclosure.

Referring to the drawings, and particularly FIGS. 1 and 2 thereof, therefrigeration system shown therein as embodying the invention comprises,in general, a compressor 10 receiving low pressure gaseous refrigerantat its inlet end via the line 11 from a suction trap 12 to whichrefrigerant is conducted by way of line 13 from the cooling coils 14(only one of which is shown), the high pressure discharge side of thecompressor 10 being connected by line 15 to a water cooled condenser 16'which in turn communicates through line 17 with a high pressure receiver18 from which liquid refrigerant may be conducted as required back tothe cooling coils 14 by way of line 19.

The compressor 10 may be of conventional construction driven in theusual manner by an electric motor or the like, and suitable commerciallyavailable controls such as thermostatic expansion valves 2t) may bepro-; vided for the cooling coils. Likewise, the condenser 16 andreceiver 18 may be of conventional construction and may either consistof two separate units as illustrated, or they may be combined in asingle combination cendenser-receiver unit. As is customary, water iscircu lated by way of the line 21 through the heat exchange coils of thecondenser 16, and high pressure gaseous refrigerant from the compressordischarge line 15 is condensed to liquid form in the condenser 16 and isstored in the receiver 18 until ready for use in the cooling coils orevaporators 14. Following evaporation of the refrigerant for the desiredcooling effect, the refrigerant is returned to the compressor 10 throughthe suction lines 13, 11 to thereby complete the cycle, the suction trapor accumulator 12 being interposed in the suction line in advance of thecompressor to collect any return-- ing liquid refrigerant whilepermitting the evaporated refrigerant to return to the compressor thusprotecting the compressor against possible damage from slugs of liquidrefrigerant. To maintain a proper liquid level in the trap oraccumulator 12 suitable float switches 22, 23 areprovided which areadapted to start and stop the pump 25 as will hereafter more fullyappear.

In accordance with the invention, novel means in the form of anautomatically operable free piston pump v25 energized by the highpressure gaseous refrigerant in the system are provided for pumping lowpressure liquid refrigerant from the suction trap or accumulator 12 tothe receiver 18 under pressure for use in the cooling coilsorevaporators 14, the liquid refrigerant thus bypassing the compressor.

This pump 25comprises, in general, a casing 26 hav ing a relativelylarge displacement chamber 27 therein and somewhat smaller displacementchambers 28, 29 on opposite sides of the central displacement chamber27," the chambers 27, 28, 29 housing a free dilferential dis-' placementpiston having a large diameter engine piston portion 30 reciprocable inthe chamber 27 and oppositely directed small diameter pump pistonportions 31, 32'- attached thereto or formed integral therewith andreciprocable within the chambers 28, 29, respectively.

The large displacement chamber 27 housing the engine piston 39 hasinletports. 33,, 34 at opposite ends e e t.

communicating with the high side of the condenser 16 through a line 35,the inlets 33, 34 being under the control of solenoid valves 36, 37,respectively, to alternately admit high pressure refrigerant gas toopposite sides of the engine piston 30. The large displacement chamber27 also has outlet or exhaust ports 38, 39 at its opposite ends whichcommunicate by way of line 40 with an upper portion of the suction trapor accumulator 12 above the liquid level therein, the outlet ports 38,39 likewise being under control of solenoid valves 41, 42, respectively,to alternately exhaust gas from opposite sides of the piston 30 to thelow pressure side of the system as the piston is reciprocated by thehigh pressure gas.

The small displacement chambers 28, 29 housing the pump pistons 31, 32are, in turn, provided with inlet ports 43, 44, respectively,communicating past one Way check valves 45, 46 via line 47 with thelower end of the suction trap or accumulator 12 below the liquid leveltherein. Also, the chambers 28, 29 are provided with outlet ports 48,'49, respectively, communicating past one way check valves 50, 51 withthe high pressure receiver 18 by way of the line 52 which has a checkvalve 53 therein to prevent back fioW. It is thus apparent that as thedifferential piston is reciprocated by the admission of high pressurerefrigerant gas alternately to opposite sides of the large engine piston30, the smaller pumping, pistons 31, 32 draw liquid refrigerant from thesuction trap 12 and force the same under pressure to the high pressurereceiver 18, the liquid refrigerant thereby by-passing the compressor10.

The action of the pump 25 is entirely automatic and is controlled by thepump itself. For this purpose, means in the form of a suitable controlelement or switching member 55 is provided which is carried by orotherwise placed under the action of the dilferential piston, theelement 55 being shown in the present instance as being attacheddirectly to the small pump piston 32 and extending through the adjacentend of the casing 26. As the control element 55 is reciprocated by thepump piston, it alternately energizes electrical coils S6, 57 thuslikewise alternately energizing the solenoids 37, 42 and 36, 41,respectively, causing the same to open their respective valves. As isapparent from FIG. 3 which shows a typical wiring diagram, the switches58, 59 on the electronic panel 60 are energized respectively by thecoils 56, 57, but the relays 61, 62 are dependent not only upon theaction of the switches 58, 59 but also upon the action of the floatswitches 22, 23 on the accumulator 12 which act to complete theelectrical circuit through the 2-pole magnetic relay 63 when the highlevel float switch 22 closes and to break the circuit through the relay63 and thereby stop the pump when the low level float switch 23 closes.

Thus, when the liquid level in the trap or accumulator 12 reaches apredetermined high level, the switch 22 is actuated to complete thecontrol circuit through relay 63 and start operation of the pump 25. Asthe differential piston reciprocates by admission of high pressuregaseous refrigerant to one or the other sides of the large piston 30,the control element 55 is moved with the piston to contact one or theother of the coils 56, 57 and thereby cause closing of the correspondingswitch 58, 59 to thus energize the corresponding sets of solenoids 37,42 and 36, 41 through the relays 61, 62, respectively. The inlet ports34, 33 from thehigh pressure side are thereby alternately opened to theengine piston chamber 27 while the exhaust ports 39, 38 aresimultaneously alternately opened, and the differential piston isautomatically reciprocated to pump liquid refrigerant from theaccumulater 12 to the receiver 18 under pressure by action of thepumppistons 31, 32.

It should. be understood that it is not desired or intended to limitthis invention to the exact details of m sses 4 l .0 modest. operationerein hown. a d s ri e si ce. various modifications within the scope ofthe appended claims may occur to persons skilled in the art to which theinvention pertains.

I claim;

I. AYefrigerating system comprising, a compressor having a suction line'for returningevaporated refrigerant to the compressor and a highpressure gaseous refrigerant line connected with a condenser, a receiverconnected withsaid condenser, an accumulator interposed in thesuctionline for collecting liquid refrigerant passing through saidsuction line to prevent delivery thereof to the compressor, and areciprocating piston type pump for pumping liquid refrigerant from saidaccumulator to said receiver under pressure, the piston of said pumpbeing operable by high pressure gas from said condenser.

2. A refrigerating system, as defined in claim 1, in which the pump hasa differential area displacement piston, the large diameter portion ofwhich constitutes the piston driving portion operable by the highpressure gas and the small diameter portion of which constitutes theliquid pumping. portion.

3. A refrigerating system comprising, a compressor having a suction linefor returning evaporated refrigerant to the compressor and a highpressure gaseous refrigerant line connected with a condenser, a receiverconnected with said condenser, an accumulator interposed in the suctionline for, collecting liquid refrigerant passing through said suctionline to prevent delivery thereof to the compressor, a reciprocating freepiston pump for pumping liquid refrigerant from said accumulator to saidreceiverunder pressure, said pump piston being operable by. highpressure gas from said condenser and being con: trolled by solenoidoperated valves, and means responsive to the movement of the pump pistonfor energizing the solenoids to operate said valves.

4. A refrigerating system, as defined in claim 3, in which the pump hasa differential area displacement piston, the larger. diameter portion ofwhich constitutes the piston driving portion operable by the highpressure gas and controllable by the solenoid valves and the smalldiameter portion of which constitutes the liquid pumping portion.

5. A refrigerating system comprising, a compressor having a suction linefor returning evaporated refrigerant to the compressor and a highpressure gaseous refrigerant line connected with a condenser, a receiverconnected with said condenser, an accumulator interposed in the suctionline for collecting liquid refrigerant passing through said suction lineto prevent delivery thereof to the compressor, a reciprocating freepiston pump for pumping liquid refrigerant from said accumulator to saidreceiver under pressure, said pump piston being operable by highpressure gas from said condenser and being controlled by solenoidoperated valves, an electrical circuit for said solenoid valves, meansresponsive to the liquid level in said accumulator for opening andclosing said circuit, and means responsive to the movement of the pumppiston for alternately energizing the solenoids to operate said valves.

6. A refrigerating system, as defined in claim 5, in which the pump hasa diiferential area displacement pis-. ton, the larger diameter portionof which constitutes the piston driving portion operable by the highpressure gas admitted alternately to. opposite sides thereof undercontrol of the solenoid valves and the small diameter portion ofwhichconstitutes the liquid pumping portion.

7. A refrigerating system comprising, a compressor having a suction linefor returning evaporated refrigerant to the compressor and a highpressure gaseous refrigerant line connected with a condenser, a receiverconnected with said condenser, an accumulator interposed in the suctionline for collecting liquid refrigerant passing through said suction lineto prevent delivery thereof to construction or to the precise componentsof the, system the compressor, a reciprocating free piston combinedengine-pump for pumping liquid refrigerant from said accumulator to saidreceiver under pressure, said enginepump being operable by high pressuregas from said condenser and being controlled by solenoid operatedvalves, an electrical circuit for said solenoid valves, means responsiveto the liquid level in said accumulator for opening and closing saidcircuit, and a control element carried by the pump piston and movabletherewith for alternately energizing the solenoids through a pair ofswitches to operate said valves.

8. A refrigerating system, as defined in claim 7, in which theengine-pump has a difierential area displacement piston, the largerdiameter portion of which constitutes the piston reciprocating portionoperable by the high pressure gas admitted alternately to opposite sidesthereof under control of the solenoid valves and the small diameterportion of which constitutes the liquid pumping portion carrying thecontrol element.

9. A refrigerating system comprising, a compressor having a suction lineconnected to the low pressure side of the system for returningevaporated refrigerant to the compressor and a discharge line connectedto the high pressure side of the system for conducting high pressuregaseous refrigerant thereto, and a reciprocating piston type pump forcirculating liquid refrigerant within the low pressure side of thesystem, said pump being connected with the high pressure side of thesystem and being operable by the high pressure gas therein.

10. A refrigerating system, as defined in claim 9, in which the pump hasa driving piston portion and a pump piston portion, the driving portionbeing connected with and operable by the high pressure gas and theliquid pumping piston portion being connected with the low pressure sideof the system for delivering liquid refrigerant thereto.

References Cited in the file of this patent UNITED STATES PATENTS2,265,558 Ward Dec. 9, 1941 2,570,979 Phillips Oct. 9, 1951 2,590,741Watkins Mar. 25, 1952 2,724,240 Sloan Nov. 22, 1955 2,836,966 KocherJune 3, 1958 2,871,673 Richards Feb. 3, 1959

